GLOUCESTER POINT, Virginia, February 24, 2020 (ENS) – “Microplastics are a global phenomenon that can’t be adequately understood or addressed in the context of the marine environment alone,” says Professor Rob Hale of William & Mary’s Virginia Institute of Marine Science, VIMS. “Plastics are produced, used, and discarded on land, and disperse through soils, rivers, and the atmosphere. The cat’s already out of the bag if you’re talking about dealing with these materials after they’ve reached the ocean.”
Professor Hale is lead author of a new “Grand Challenges” paper commissioned to mark the 100th anniversary of the American Geophysical Union, the world’s largest association of Earth and space scientists with more than 60,000 members in 137 countries.
The paper, “A Global Perspective on Microplastics,” published in the January issue of the “Journal of Geophysical Research: Oceans,” is co-authored by VIMS doctoral student Meredith Seeley and senior research scientist Dr. Mark LaGuardia, along with Drs. Lei Mai and Eddy Zeng of Jinan University in Guangzhou, China.
American Geophysical Union Executive Director and CEO Chris McEntee says the Grand Challenges, “represent a special collection of open-access review papers with the shared goal of transforming Earth and space science to meet the challenges of today and the opportunities of tomorrow.”
“They explore where major research and discovery are needed to address fundamental questions in our understanding of Earth and the solar system,” McEntee said.
Microplastics, plastic pieces less than five millimeters across, are about the size of a tiny red ant.
Used in manufacturing, industry, and 3D printing, microplastics are manufactured for consumer products such as synthetic fabric, toothpaste, and cosmetics, and they also are formed when larger plastics break apart into tiny beads.
When microplastics wash down a drain, they are not removed by wastewater treatment and create problems in the environment. Microplastics are now found everywhere in the ocean and coastal waters, shorelines, ocean seabed, and sea surfaces. There has been widespread concern among scientists and the public that these minute synthetic fragments are impacting marine ecosystems.
“It’s not just an ocean problem,” says Professor Hale. “There’s growing evidence that microplastics are distributed across the land surface and in the air.”
Wind plays a role in carrying microplastics to the streets of European cities and remote areas of the Arctic Ocean, where ecosystems are already stressed by the effects of climate change. The high concentrations of microplastics found in snow samples from many different regions suggest microplastics, which may contain varnish, rubber, or chemicals used in synthetic fabrics, contribute to air pollution. Previous studies have shown that microplastics may contribute to lung cancer risk, highlighting an urgent need to further assess the health risks of inhaling them.
Major sources of microplastics include agricultural runoff, aquaculture, cruise ships, ocean dumping, stormwater, the shipping and fishing industries, urban runoff and waste management. Microfibers shed from synthetic clothing and fishing nets are a form of microplastic.
These fibers, beads, and microplastic fragments can all absorb harmful pollutants like pesticides, dyes, and flame retardants, only to later release them in the ocean.
Scientists have even found microplastic particles in rain. They saw it in the rain falling on the Pyrenees mountains in southern France. It has been found on remote and otherwise pristine islands.
In an August 2019 study, researchers with the U.S. Geological Survey discovered multicolored microplastic shards, beads and fibers in more than 90 percent of rainwater samples taken from across Colorado, including samples from locations more than two miles (3,000 meters) high in Rocky Mountain National Park.
On December 28, 2015, President Barack Obama signed the Microbead-Free Waters Act of 2015, banning plastic microbeads in cosmetics and personal care products, but they persist in the physical environment.
And the VIMS researchers note that the global scope of the microplastics issue extends to the social sphere as well.
“We have to recognize that microplastic pollution is an international problem that doesn’t respect political boundaries,” says Seeley. “As with climate change and species management, developed and emerging nations will have to cooperate to find equitable solutions.”
Not All Microplastics are Created Equal
Plastic” is a catch-all term for a complex array of materials that vary in chemical composition, size, texture, and shape. Plastics are often infused with additives, including flame retardants and UV inhibitors, which may themselves have environmental and health impacts.
“People often assume that all plastics are the same and behave identically in the environment,” says Hale, “but that isn’t the case at all. To resolve key questions and mitigate possible impacts, everyone – manufacturers, scientists, health-care specialists, engineers, economists, policymakers, and others – must collaborate to better understand the composition and nature of plastic products and their additives.”
The VIMS researchers stress that the characteristics of microplastics can and do change during and after use. “The complexity of microplastics becomes even more convoluted once they enter the environment and begin to intermingle and weather,” says LaGuardia. “We have to better understand these complexities, especially in transition zones such as estuaries.”
The researchers insist that a comprehensive understanding of the microplastics issue, and the most effective responses, will require better analytical tools than scientists have today.
“To understand the real impacts of microplastics,” says Hale, “we’ve got to improve our sampling and analytical capabilities, including the ability to study nanoplastics and weathered materials.”
Nanoplastics are particles even smaller than microplastics, with sizes ranging from one nanometer to 1,000 nanometers or a micron. A sheet of paper is about 100,000 nanometers thick.
Hale says current state-of-the-art microscopes, “provide really great information when you zero in on a single microplastic particle.” The problem, he says, is that many samples contain thousands of different particles, and many of these particles are really, really small.
“There’s a disconnect,” says Hale. “A lot of our technology can’t get down to stuff below 10 microns, and in terms of effects on organisms, we think that smaller particles may be more toxic.”
Trying to bridge this gap, VIMS recently received funding from the NOAA Marine Debris Program to investigate interactions between particles smaller than 10 microns and infectious disease in fish.
The VIMS authors’ concerns regarding microplastics extend to potential impacts on human health.
“There have been concerns about ingesting microplastics from seafood, but the indoor environment is our biggest direct threat,” says Hale. “Many people in developed countries spend almost all their time indoors, in spaces that are increasingly air-tight and insulated with things like polystyrene foam. Our exposure to microplastics from breathing and ingesting indoor dust may have toxicological consequences, but there’s been very little research.”
To answer these concerns, Hale and colleagues at VIMS are acquiring a time-of-flight mass spectrometer, which will allow them to better analyze chemical contaminants associated with microplastics and other environmental samples.
“This will help us start going after all these unknown additives in plastics and open up that Pandora’s Box a little better,” says Hale. “I think that’s where the action really is in terms of human health.”